Musings on genome medicine: is there hope for ethical and safe stem cell therapeutics?

Cell therapy of some sort has been available for many years, most notably hematopoietic cell therapies, which use adult bone marrow stem cells to treat the donor themselves or a related person. Commercial products, such as Carticell, Epicell and limbal stem cells, are used worldwide for tendon repair and esthetic surgery. More recently, allogenic transplants and xenotransplants of skin, pancreatic islets, cord blood or mesenchymal stem cells have been used, and trials involving embryonic stem cell (ESC)-derived [1] and fetal-derived neural stem cells [2] have been approved.Three different modalities of cell therapy have emerged that take into account the differing regulations governing processed and unprocessed cells [3]. First is a personalized medicine point-of-contact model, in which cells are harvested from the same (or a related) individual, undergo minimal processing and are delivered immediately to the recipient. Second is a model akin to what is used for cord blood, which involves an indeterminate period of storage with minimal processing. And third is a drug-delivery model, in which the manufactured product (cells in this case) is approved under a Biologic License Application (BLA). Under any model, the ethical and safety issues raised by potential pluripotent stem cell therapies are significant hurdles that must be overcome if the medical promise of this field of research is to be realized.Most cell therapy has not provoked much controversy, but an exception is ESC therapy, about which important moral and ethical issues have been raised (reviewed in [4]). These concerns include donor and consent issues associated with obtaining eggs and the issue of destruction of embryonic human life [5]. Countries around the world have enacted guidelines defining what is permissible for pluripotent stem cell research. These regulations range from an outright ban on such work to narrowly defined permissions [6]. All these guidelines reflect decisions about when during emb